fix(hooks): address Greptile review on PR #28703

Resolves two findings from the automated code review:

1. CONTRIBUTING.md: shrink the new Conventional Commits / Branches
   section to a 2-line pointer at docs.litellm.ai. Per the team
   convention, the full documentation lives in the litellm-docs
   repo — see BerriAI/litellm-docs#208 for the companion change that
   adds the section to docs/extras/contributing_code.md.

2. .githooks/commit-msg: tighten the subject regex to also reject an
   uppercase first letter in the description. CI's subjectPattern is
   ^(?![A-Z]).+$ so the previous local hook would accept 'feat: Add
   thing' which would then fail the PR-title check. The local hook is
   now the strictly tighter of the two gates. Test cases extended to
   cover both the new rejection and the digit/symbol-start cases that
   remain allowed.

Resolves LIT-3306

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.githooks/commit-msg

@@ -43,7 +43,11 @@ case "$subject" in
 esac
 
 ALLOWED_TYPES="feat|fix|docs|style|refactor|perf|test|build|ci|chore|revert"
-PATTERN="^(${ALLOWED_TYPES})(\([^)]+\))?!?: .+"
+# Description must not start with an uppercase letter — kept in sync with the
+# subjectPattern in .github/workflows/conventional-commits.yml so the local
+# hook is the strictly tighter of the two gates. (Without this guard, a commit
+# like "feat: Add thing" passes locally but fails the PR-title CI check.)
+PATTERN="^(${ALLOWED_TYPES})(\([^)]+\))?!?: [^A-Z].*"
 
 if printf '%s' "$subject" | grep -Eq "$PATTERN"; then
     exit 0
@@ -55,6 +59,7 @@ cat >&2 <<EOF
   Got:      $subject
 
   Expected: <type>(<scope>)!: <description>
+            (description must start with a lowercase letter)
 
   Allowed types: feat, fix, docs, style, refactor, perf, test, build, ci, chore, revert
   Examples:

CONTRIBUTING.md

@@ -55,65 +55,7 @@ That's it! Your local development environment is ready.
 
 ## Commit and Branch Conventions
 
-LiteLLM enforces two community specs:
-
-- **Commits** follow [Conventional Commits 1.0.0](https://www.conventionalcommits.org/en/v1.0.0/) — `<type>(<scope>)!: <description>`
-- **Branches** follow [Conventional Branches](https://conventional-branch.github.io/) — `<type>/<description>`
-
-### Commit message format
-
-```
-<type>(<optional scope>)!: <description>
-
-<optional body>
-
-<optional footer>
-```
-
-Allowed `<type>` values: `feat`, `fix`, `docs`, `style`, `refactor`, `perf`, `test`, `build`, `ci`, `chore`, `revert`. Add `!` before `:` for breaking changes.
-
-Examples:
-```
-feat(router): add weighted round-robin strategy
-fix(bedrock): decouple STS region from aws_region_name
-chore(deps): bump black to 26.3.1
-refactor!: drop Python 3.8 support
-```
-
-PR titles must follow the same format — squash-merge uses the PR title as the commit subject, and a CI check validates it.
-
-### Branch naming
-
-Format: `<type>/<short-description>` where `<type>` is one of `feature`, `bugfix`, `hotfix`, `release`, `chore`.
-
-Examples:
-```
-feature/weighted-round-robin
-bugfix/streaming-empty-chunks
-chore/bump-black
-hotfix/auth-bypass
-```
-
-Branches always allowed (bypass the check): `main`, `litellm_internal_staging`, `dependabot/*`, `gh-readonly-queue/*`.
-
-### Installing the hooks
-
-The hooks live in `.githooks/` and are opt-in. Run once per clone:
-
-```bash
-make install-hooks
-```
-
-This sets `core.hooksPath=.githooks` for the local repository. The hooks run on `git commit` (subject validation) and `git push` (branch validation).
-
-In a rare emergency you can bypass them per-command:
-
-```bash
-git commit --no-verify -m "..."
-git push   --no-verify
-```
-
-To uninstall: `git config --unset core.hooksPath`.
+Commits follow [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/) and branches follow [Conventional Branches](https://conventional-branch.github.io/). Run `make install-hooks` once per clone to enable the local git hooks that enforce these — see the [contributor docs](https://docs.litellm.ai/docs/extras/contributing_code#commit-and-branch-conventions) for the full type list, examples, the protected-branch bypass list, and how to opt out.
 
 ### 2. Development Workflow
 

tests/test_litellm/test_git_hooks.py

@@ -104,6 +104,13 @@ def test_commit_msg_accepts_conventional_subjects(tmp_path, subject):
         "ux: thing",                          # unknown type
         "Feat(router): capital type",         # types are lowercase
         "feat(router):",                      # empty description
+        # Description must start with a lowercase letter — kept in sync with
+        # the CI workflow's subjectPattern so the local hook never accepts a
+        # subject that CI will later reject.
+        "feat: Add thing",
+        "fix(router): Decouple something",
+        "chore: BUMP deps",
+        "feat: A",
     ],
 )
 def test_commit_msg_rejects_invalid_subjects(tmp_path, subject):
@@ -115,6 +122,25 @@ def test_commit_msg_rejects_invalid_subjects(tmp_path, subject):
     assert "Conventional Commits" in result.stderr
 
 
+@pytest.mark.parametrize(
+    "subject",
+    [
+        # Lowercase letter — the common case.
+        "feat: lowercase start is fine",
+        # The CI's `^(?![A-Z]).+$` rejects only uppercase A-Z, so digits and
+        # symbols are still allowed; mirror that behavior here.
+        "feat: 1-based indexing now works",
+        "fix(deps): @types/node bump",
+    ],
+)
+def test_commit_msg_accepts_non_uppercase_starts(tmp_path, subject):
+    result = _run_commit_msg(subject, tmp_path)
+    assert result.returncode == 0, (
+        f"hook rejected a valid non-uppercase-start subject:\n"
+        f"  subject: {subject!r}\n  stderr: {result.stderr}"
+    )
+
+
 @pytest.mark.parametrize(
     "subject",
     [